Christopher G. Morgan and Ronald Vane, XEI Scientific, Inc., Redwood City, CA
Paper presented at SPIE Advanced Lithography Conference Feb. 14, 2012, San Jose CA.
Many lithographic tools require carbon-free vacuum environments. A commercially available low-power (<20W) downstream plasma system which produces oxygen radicals in the 0.2-0.6 Torr pressure range has been shown to be effective in removing carbon contamination from standard SEM and FIB tools. However, in larger systems such as wafer or mask inspection tools the extent of cleaning in this pressure range is limited. A new downstream plasma system optimized for larger chambers has been developed which operates at higher power and lower pressure. Cleaning rates of over 1 nm/minute have been measure from over 0.5 m away from the plasma source.